Power systems such as electrical power distribution or transmission systems are used to supply, transmit and use electric power. High Voltage Direct Current (HVDC) power transmission is becoming increasingly important due to increasing need for power supply or delivery and interconnected power transmission and distribution systems.
Power systems such as electrical power distribution or transmission systems generally include a protection system for protecting, monitoring and controlling the operation and/or functionality of other components included in the power system. Such protection systems may for example be able to detect short circuits, overcurrents and overvoltages in power lines, transformers and/or other parts or components of the power system. The protection systems can include protection equipment such as circuit breakers for isolating any possible faults for example occurring in power transmission and distribution lines by opening or tripping the circuit breakers. After the fault has been cleared, e.g. by performing repairs and/or maintenance on the component in which the fault has been detected, the power flow can be restored by closing the circuit breakers. In alternative or in addition, the protection systems can be arranged to, upon detection of a fault in a particular route for power flow, isolate the route in which the fault has been detected and select an alternative route for the power flow. Operation of the circuit breakers may be responsive to detection of a fault condition or fault current. Upon detection of a fault condition or fault current, a mechanism may operate the circuit breaker so as to interrupt the current flowing there through. Once a fault has been detected, contacts within the circuit breaker may separate in order to interrupt the current there through. Spring arrangements, pneumatic arrangements or some other means utilizing mechanically stored energy may be employed to separate the contacts. Mechanical current interrupters may for example be employed in circuit breakers.
An HVDC grid or a DC grid may comprise multiple alternating current (AC)/DC converter terminals interconnected by transmission lines, e.g., underground cables and/or overhead lines. Within the grid, a terminal may be connected to multiple terminals resulting in different types of topologies. DC circuit breakers can be used for isolating faulty components, such as transmission lines, in HVDC and DC grids.